Disk drives are often used to record data onto or to reproduce data from a recording media. A disk drive can include a rotating magnetic disk and a head actuated over the disk to magnetically write data to and read data from the disk. The disk includes a plurality of radially spaced, concentric tracks for recording user data.
The storage device industry is always trying to increase the recording density of the disk, or in other words, the amount of data that can be stored in a given area on the disk. Shingled magnetic recording (SMR) has recently been introduced as a way of increasing the number of tracks per inch (TPI) by making the tracks narrower. Since it is technologically easier to read narrow tracks than to write narrow tracks, SMR increases TPI by using a relatively wide shingle write head with a stronger magnetic field to overlap tracks like roof shingles. The non-overlapping portion then serves as a narrow track that can be read by a narrower read head.
However, this overlap can create a problem when writing data since new writes to a previously overlapped track affects data written in the overlapping track. In addition, due to the stronger magnetic field of the write head, data in several adjacent tracks in either an inside diameter direction or an outside diameter direction of the disk can be affected depending on a direction of overlap. This problem is known as adjacent track interference (ATI). Thus, SMR presents additional challenges not present in conventional disk drives.
In addition to SMR technology, non-volatile flash memory is becoming increasingly popular as a storage medium due to its data transfer speeds, size, and durability. However, as with SMR technology, flash memory also presents its own unique challenges in managing data. For example, portions of flash memory may become unusable after a high number of writes. In addition, the capacity of flash memory may be limited due to the extra cost of providing large amounts of flash memory.
Due to the different advantages provided by various types of storage media, computer systems and/or storage devices may combine different types of storage media. However, efficiently managing files among various types of storage media can prove difficult due to the different limitations of the various types of storage media.